Expertly designed custom nodes for Google Gemini integration in ComfyUI, featuring a robust multi-key retry system to eliminate server errors and rate limits.

🌟 Key Features

🛡️ 3-Key Iterative System (API Fallback)

Stop worrying about "Server Error 500" or rate limits. These nodes allow you to input up to 3 different API keys. If the primary key fails, the system automatically rotates to the next one and retries up to your configured max_retries.

🎨 Gemini 3 Pro Image (API Fallback)

Generate stunning high-fidelity images directly from ComfyUI using the latest gemini-3-pro-image-preview model.

Native Resolutions: 1K, 2K, and 4K support.
Aspect Ratio Control: Auto, 1:1, 16:9, 9:16, 21:9, and more.
Visual Context: Support for image inputs to guide generation (Multimodal).

📝 Gemini 3 Pro (API Fallback)

The ultimate tool for prompt engineering, image analysis, and creative writing.

Versatile Models: Includes gemini-3-pro-preview, gemini-2.5-pro, gemini-2.5-flash, and specialized previews.
Image-to-Text: Upload images to get detailed descriptions or use them as a reference for new prompts.
Clean UI: Streamlined parameters focused on results.

🔑 Crucial: Setting up your Google API Keys

To use Gemini-3-Pro-Image models, you must enable billing in your Google Cloud project and verify your quotas. Otherwise, you will encounter a Limit: 0 error.

⚠️ Troubleshooting "Limit: 0" or "429 RESOURCE_EXHAUSTED"

If you get an error saying limit: 0, even with billing enabled:

Model Quota: Image models (gemini-2.0-flash or imagen) have a separate quota. Go to Google Cloud Console > Quotas and search for generativelanguage.googleapis.com/generate_requests_per_model_per_day.
Project Tier: Return to Google AI Studio, go to Settings > Plan, and confirm your project is on the "Pay-as-you-go" plan. If it says "Free", click "Edit" and choose your Billing project.
Region: Some image models are only available in certain regions. Ensure your project is not restricted.

1. Get your API Keys

Go to Google AI Studio.
Sign in with your Google Account.
Click on the "Get API key" button on the top left sidebar.
Click "Create API key in new project".
Copy your API Key and repeat to get up to 3 keys if you want full fallback protection.

2. Enable Billing (Required for Image Generation)

By enabling billing, you move to the "Pay-as-you-go" tier which unlocks the quota for image models.

Note: Google often provides $300 in free credits for new accounts, which covers a significant amount of usage.

Go to the Google Cloud Console.
Select your project from the top dropdown.
Navigate to Billing in the sidebar menu.
Click "Add billing account" and enter your payment information.
Link your project: In the "Account Management" tab of the Billing section, ensure your project is linked to the new billing account.
Set Budget Alerts (Highly Recommended): In the "Budgets & Alerts" menu, create a budget (e.g., $1 or $5) to receive email notifications and avoid unexpected charges.

3. Verify in AI Studio

Return to Google AI Studio, go to Settings/Plan, and confirm your project is now on the "Pay-as-you-go" plan. This will replace the "Limit: 0" with a functional quota.

🛠️ Installation

Navigate to your ComfyUI custom_nodes folder.

Clone this repository:

git clone https://github.com/USER/ComfyUI-Gemini3-API-Fallback

Install dependencies:

python -m pip install google-genai pillow numpy torch

⚙️ Configurable Parameters

api_key_1, 2, 3: Your iterative keys.
max_retries: Number of full rotation rounds to attempt before giving up (Default: 10).
English Logging: Real-time console feedback on key rotation and server wait times.